A closed solenoidal induction coil can be used to inductively heat a material by passing the material through the coil while alternating current of a suitable frequency is supplied to the coil. Closed induction coils can be difficult to maintain. Electromagnetic shielding of induction coils is typically required to meet industrial and personal standards.
U.S. Pat. No. 4,761,530 discloses a box-like inductor assembly having an openable side door so that the inductor assembly can be laterally moved away from a continuous metal strip surrounded by the inductor assembly when the side door is closed. U.S. Pat. No. 5,317,121 discloses an induction coil having a gap through which through which a continuous metal strip can move laterally through so that it is either surrounded by the coil or moved out of the coil. U.S. Pat. No. 5,495,094 discloses various induction coils having a gap through which a continuous metal strip can move laterally through. U.S. Pat. No. 5,837,976 (“the '976 patent”) discloses various arrangements of induction coils having a gap through which a continuous metal strip can move laterally through. In some embodiments, the '976 patent discloses flexible interconnecting member(s) of the induction coil so that the flexible interconnecting member(s) can be spread apart to increase the size of the gap as shown in FIG. 9a, FIG. 9b, FIG. 10a and FIG. 10b of the '976 patent.
International Publication No. WO 2005/004559 A2 discloses an electromagnetic shield for use with induction coils incorporating a gap as described, for example, in the above patents. The electromagnetic shield also incorporates at least one gap so that a continuous metal strip can move laterally in and out of the induction coil and surrounding electromagnetic shield through the gaps in the induction coil and electromagnetic shield.
International Publication No. WO 2007/081918 A2 discloses an electromagnetically shielded induction heating apparatus that includes a substantially gas tight enclosure and electromagnetic shield material. The induction heating apparatus/coil surrounding the gas tight enclosure is not openable.
Japanese patent publication JP 63-4873 (published 1988 and now in the public domain) discloses a method of blowing hot air through a non-openable induction furnace to prevent the formation of dew from vapors released by a coating material in the furnace.
It is one object of the present invention to provide an electromagnetically shielded openable induction coil that can be conveniently opened for maintenance with minimal disturbance of a surrounding electromagnetic shield structure that forms an inductor assembly with the coil.
It is another object of the present invention to provide an electromagnetically shielded inductor assembly having an openable induction coil that can be easily inserted or removed from the electromagnetically shielded enclosure, and can be opened while the induction coil is in the electromagnetically shielded enclosure without complete disassembly of the enclosure.
It is another object of the present invention to provide an electromagnetically shielded inductor assembly having an openable induction coil that can be provided with a static or dynamic seal between the interface regions of the openable induction coil and the electromagnetically shielded inductor assembly so that a gastight seal can easily be maintained between the induction coil and the electromagnetic shield inductor assembly when the induction coil is in the closed position while maintaining an efficient method of opening and re-closing the induction coil without resealing of the seal.
It is another object to the present invention to provide apparatus and a method of injecting a gas into an induction furnace having an openable induction coil as an improvement to the disclosure of Japanese patent publication JP 63-4873.